In a passive optical network (PON), one central office OLT (optical line terminal) is corresponding to at least one ONU (optical network unit) or ONT (optical network terminal). Because an ONT may be considered as a special ONU, an ONT and an ONU are collectively referred to as an ONU in the following description of this specification.
In a downstream direction, downstream information of an OLT is sent to all ONUs by using a fixed downstream optical wavelength. In an upstream direction, all ONUs emit light in a specific timeslot according to a rule of time division multiplexing of upstream optical path bandwidth, that is, the ONUs emit upstream light according to a bandwidth assignment instruction of the OLT, while a rogue ONU is an ONU that does not emit light according to a bandwidth assignment instruction of the OLT.
There are many types of rogue ONUs. By a light emission time of a rogue ONU, the rogue ONUs may be classified into the following types.
(1) A continuous-mode rogue ONU
Such an ONU emits light at any moment. When an ONU emits light continuously, the ONU occupies all upstream timeslots of an upstream optical wavelength, and consequently, another ONU cannot upload information and a data stream, while in this case, information and a data stream can still be normally delivered in a downstream direction. There are many means for detecting, checking, and isolating such a continuous-mode rogue ONU, and such an ONU is a conventional rogue ONU.
(2) A rogue ONU that advances or delays light emission within a range granted by an OLT
Within a time period granted by the OLT, the rogue ONU may advance light emission, delay turn-off, or the like, and consequently affects an “adjacent” ONU. Such a rogue ONU can be effectively processed by using a particular means.
(3) A rogue ONU that irregularly emits light beyond a range granted by an OLT without following a rule
Such a rogue ONU emits light at random, and it is extremely difficult to detect, check, and isolate the rogue ONU.
Currently, technologies for detecting, checking, and isolating a rogue ONU are summarized as follows: Interoperability of overall solutions of all manufacturers is poor; it is time-consuming to detect and check some rogue ONUs, a service interruption time is long, and the like. In most of existing rogue ONU detection technologies, whether a rogue ONU exists is determined according to whether light is received at an “idle moment” of an OLT. The “idle moment” may be a dedicated time window that is specially used by the OLT to measure a rogue ONU, or may be an idle moment not granted by the ONU. The OLT determines, according to whether light is received at an idle moment, whether a rogue ONU is connected to the OLT. To ensure detection accuracy, a mechanism of multiple detections and repeated confirmation is generally used. With this method, a continuous-mode rogue ONU and a rogue ONU that advances or delays light emission within a range granted by an OLT can be identified. On the basis of completing identification of a rogue ONU, the rogue ONU is isolated.
In addition, some new types of rogue ONUs have not yet been known. A rogue ONU involved in the present invention is a new type of rogue ONU. When the rogue ONU is faulty, a notification is given on an operational interface that an ONU ID (Identifier, identifier) in a system cannot be used. Currently, this new type of rogue ONU has not yet been widely known in the industry, and there is no relatively effective processing method. In a network with a high split ratio, an operator still needs to spend a relatively long time in manually inserting/removing a fiber on/from an ODN, and then observing a behavior of going online of ONUs on an OLT to check rogue ONUs one by one. Consequently, efficiency is low.